2-4 hours, depending on how lost you get and how much you stop to enjoy the great views.

From Invemere, drive towards Panorama. ~10 minutes past Wilmer, you will see signed Lillian Lake Picnic Area on the right. Park. Ride back on road about 1 minute to gate on right. Go through it; trail starts on left by painted rocks.

Opinion. A pretty mountain bike ride through dry forests. The route is somewhat silly for the first half, as it just weaves in and around itself to add length - I found I spent more time trying to stay on trail than looking at the scenery. But when it gets to Toby Creek, it pays off - fantastic views over the canyon. If you do this backwards, it will get you to Toby Creek quickly and thus the last half doubles as a good hike.

Fact. Weaving / overlapping / contorted trail (first half) through beautiful open forest that eventually comes to great trail overlooking Toby Creek. Spectacular there.
Route finding. Paint is dabbed on trees and rocks. Always keep orange on left, greenish-yellow on right. Its really easy to get lost / go in circles as trails overlap, but eventually you will get to Toby Creek. The first half is rather contrived as it constantly weaves through a small area with many junctions.